The present invention relates generally to using a clamp for sealing a patient""s body tissue during introduction of medical devices, such as cannula, endoscope, aspirator, and pressure monitor. More specifically, the invention relates to a suture-free clamp for scaling atrial tissue during cardiothoracic surgeries, and providing a port in which medical devices can be inserted through the clamp without injuring the atrial tissue.
During conventional or endoscopic surgical procedures, such as open cholecystectomy or laparoscopic oophorectomy, introduction of medical devices, such as a cannula, stent, endoscope, aspirator, or pressure monitor, into a patient""s body tissue often requires an incision on the body tissue. Sutures are generally required to establish hemostasis and secure the medical device onto the body tissue. Repositioning of the medical device requires loosening or removing the sutures and re-tightening or replacing the existing sutures with new ones.
During various cardiothoracic surgeries, such as coronary artery bypass graft, heart valve repair, septal defect repair, pulmonary thrombectomy, thoracic aortic aneurysm repair, atherectomy, and removal of atrial myxoma, cardiopulmonary bypass and cardiac arrest are often required. Cardiac arrest is generally achieved by infusing cardioplegic solution through an arterial catheter into the coronary ostia or through an atrial catheter into the coronary sinus. After the myocardium is paralyzed, cardiopulmonary bypass is required to support the peripheral circulation. Deoxygenated blood is usually drained through a venous cannula from the right atrium, superior vena cava, or inferior vena cava to a bypass-oxygenator, and oxygenated blood is returned from the bypass-oxygenator to the ascending aorta through an arterial cannula to perfuse peripheral organs.
The right atrial appendage is often incised to allow insertion of the venous return cannula or cardioplegic catheter during cardiothoracic surgeries. After the cannula is placed in the right atrium, a purse string suture is often placed on the atrial tissue around the incision site to achieve hemostasis, and the suture pulled tightly against the rigid cannula to secure the cannula. Disadvantages associated with the present technique are that (1) placing sutures on the atrium is time consuming, (2) repositioning of the cannula requires manipulating sutures on the atrial tissue, i.e. loosening and re-tightening sutures around the cannula, and (3) delicate atrial structures may be damaged due to suture placement and manipulation.
Methods and devices are therefore needed for sealing body tissues during introduction of other medical devices, that eliminate the need for sutures and reduce the risk of tissue injury during manipulation of other medical devices.
The present invention provides a suture-free clamp for sealing body tissues during introduction of a medical device. The clamp may be used in either open or minimally invasive procedures. The clamp can be made of molded plastic or metal injection molded metal.
In a preferred embodiment, the clamp comprises a generally cone-shaped housing and a collar operably connected to a proximal end of the housing by a plurality of struts. The housing has an outer surface, a large diameter proximal end, a smaller diameter distal end, and a lumen therebetween. The outer surface is generally smooth and tapered from the proximal end to the distal end, thereby facilitating insertion of the clamp into a body tissue. The collar has a central opening that is aligned with the lumen of the housing and is adapted for receiving a medical device. The collar further includes an annular surface which surrounds the opening and is operable to engage an annular surface of the proximal end of the housing to clamp body tissue therebetween. The tissue is released by releasing the clamp.
In another embodiment, the struts may have a pivoting internal joint and are pivotally connected to the housing and the collar. In still another embodiment, the struts are located and operate within a plurality of distally extending slots which are included in the housing.
In still another embodiment, the lumen of the housing further includes a hemostatic valve to reduce hemorrhaging when the clamp is used, especially in a patient""s blood vessel, such as an aorta.
In still another embodiment, the housing and the collar may be constructed so that they snap together, or are bonded. The clamp may also be made from a smooth material having a spring type elastic property that provides the clamp force.
The invention also provides methods for sealing body tissues during introduction of a medical device using the suture-free clamp described above. An incision is made in a body tissue, and the distal end of the housing is introduced through the incision. The edges of the incision are stretched as the tissue advances along the widening surface of the cone, until the tissue is positioned against the annular surface of the housing. The collar is pushed distally to engage the tissue against the annular surface of the collar, so that the tissue is clamped between the annular surface of the housing and the collar, thereby sealing the body tissue. A medical device, such as a cannula, is introduced through the opening of the collar and the lumen of the housing, and advanced into the body. Alternatively, the medical device may be inserted through the collar and housing before clamping the introducer to the body tissue. In this way, the medical device can be manipulated through the lumen of the housing and repositioned inside the body tissue without disturbing the tissue, thereby reducing risk of injury to the tissue.